It has been identified that Mozilla Thunderbird improperly handles Script objects while they are being executed, allowing them to be modified during execution. JavaScript is disabled in Mozilla Thunderbird by default. Mozilla Thunderbird has also been found to be vulnerable to various potential buffer overflows. Lastly, the binary release of Mozilla Thunderbird is vulnerable to a low exponent RSA signature forgery issue because it is bundled with a vulnerable version of NSS.

Impact

An attacker could entice a user to view a specially crafted email that causes a buffer overflow and again executes arbitrary code or causes a Denial of Service. An attacker could also entice a user to view an email containing specially crafted JavaScript and execute arbitrary code with the rights of the user running Mozilla Thunderbird. It is important to note that JavaScript is off by default in Mozilla Thunderbird, and enabling it is strongly discouraged. It is also possible for an attacker to create SSL/TLS or email certificates that would not be detected as invalid by the binary release of Mozilla Thunderbird, raising the possibility for Man-in-the-Middle attacks.

Workaround

There is no known workaround at this time.

Resolution

Users upgrading to the following releases of Mozilla Thunderbird should note that this version of Mozilla Thunderbird has been found to not display certain messages in some cases. All Mozilla Thunderbird users should upgrade to the latest version: